The present invention relates to a thermal head, in particular, relates to a thermal head with improved heater material which is conditioned for strong thermal stresses.
The present thermal head is used for thermal printing on a paper.
Conventionally, a heater material for a thermal head is produced through sputtering or evaporation, and/or a thick film technique.
However, the evaporation, and the sputtering which use a vacuum device need a large apparatus, and takes long time to produce a film, and therefore, the producing cost of a thermal head must be high. And, the thick film technique which has the basic printing process utilizing paste has the disadvantage that a fine pattern can not be produced.
Another prior process for producing a heater material is chemical plating, or electroless plating, which has none of the above disadvantages. However, conventionally, a film produced through electroless plating has no superior characteristics for a thermal head. The important disadvantage of a prior film produced through electroless plating is that the resistance of a heater is not stable during thermal stress.